| 摘要 |
4-Oxaaldehydes of the formula <IMAGE> are prepared by catalytic isomerization of 1,3-dioxanes by a process in which a 1,3-dioxane of the formula <IMAGE> where R1, R2, R4 and R5 are identical or different and are each hydrogen, a straight-chain or branched alkyl, alkenyl or alkynyl radical of not more than 18 carbon atoms, a cycloalkyl or cycloalkenyl radical of 5 to 8 carbon atoms, an aryl, alkylaryl, aralkyl or alkenylaryl radical of 5 to 16 carbon atoms or a heterocyclic radical, and furthermore R1 and R2 and/or R4 and R5 together with the carbon atom to which they are bonded may form a cycloalkane, a cycloalkene or a heterocyclic structure, and the stated radicals may furthermore carry substituents which are inert under the reaction conditions, and R3 is hydrogen or straight-chain or branched alkyl, is isomerized using a phosphate as a catalyst.
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